Counterweight removal arrangement for hydraulic excavators or the like



Oct. 13, 1970 J. H. WILCOX 3,533,524

COUNTERWEIGHT REMOVAL ARRANGEMENT FOR HYDRAULIC EXCAVATORS OR THE LIKEFiled Oct. 28, 1968 if 1 g ,7

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INVENTOR JOHN H.WILCOX BY fW AT T'ORNEY 3,533,524 LIC Oct. 13, 1970 J.H. WILCOX COUNTERWEIGHT REMOVAL ARRANGEMENT FOR HYDRAU EXCAVATORS OR THELIKE 3 Sheets-Sheet 2 Filed ON. 28, 1968 INVENTOR JOHN H.WILCOX Oct. 13,1970 J H. WILCOX 3,533,524

COUNTERWEIGHT REMVAL ARRANGEMENT FOR HYDRAULIC EXCAVATORS OR THE LIKEFiled 001;. 28, 1968 5 Sheets-Sheet 5 INVENTOR JOHN H. W LCOX .ATTORNEYUnited States Patent 3,533,524 COUNTERWEIGHT REMOVAL ARRANGEMENT FORHYDRAULIC EXCAVATORS OR THE LIKE John H. Wilcox, Evansville, Ind.,assignor to Bucyrus-Erie Company, South Milwaukee, Wis., a corporationof Delaware Filed Oct. 28, 1968, Ser. No. 771,050 Int. Cl. E02f 3/00 US.Cl. 214142 4 Claims ABSTRACT OF THE DISCLOSURE A hydraulic back-hoeexcavator includes a counterweight mounted at the lower rear edge of theworking frame by means of vertical suspension members having upper endspivotally connected to the frame and lower ends pivotally connected tothe counterweight. When the front end of the frame is elevated by movingthe excavator bucket downwardly against the ground, the counterweightcan swing down and away from the frame and can thus be placed on asupporting crib and disconnected. In a preferred embodiment, thesuspension members are extensible and retractable to enable thecounterweight to be lowered slightly before the front end is elevated toinsure that the counterweight will clear the working frame. Also,provision is made for locking the counterweight to the working framewhen it is mounted, and a centering plug arrangement is provided toinsure proper orientation of the counterweight.

BACKGROUND OF THE INVENTION This invention relates to counterweightedhydraulic excavators and like machines; and, more particularly, itresides in an improved counterweight removal arrangement for suchmachines.

It is frequently desirable to have the counterweights of excavatorsreadily removable so that they can be transported separately. Variousdevices and arrangements for removing counterweights have been developedand can be found in prior art patents. Many of the prior arrangements,however, have not proven entirely satisfactory from the standpoints, forexample, of cost, complexity, strength, safety and/ or ease andefficiency of operation.

SUMMARY OF THE INVENTION The present invention contemplates acounterweight removal arrangement for a hydraulic excavator or similarmachine in which a counterweight is swingably mounted at the rear of theframe so that it can be lowered and dismounted simply by lifting thefront end of the machine. The object of the invention is to provide animproved counterweight removal arrangement of this general type which ishighly effective, strong, and readily adaptable to various machineswhile still being relatively simple and inexpensive to manufacture,assemble and use. Other objects and advantages will become apparent fromthe following description in which there are shown, by way ofillustration and not of limitation, presently preferred embodiments ofthe invention.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat schematic rear view ofa hydraulic back-hoe excavator incorporating a counterweight removalarrangement embodying the invention,

FIG. 2 is a fragmentary schematic side view of the excavator andcounterweight removal arrangement shown in FIG. 1,

FIG. 3 is a fragmentary view in cross section through the plane 33 shownin FIG. 1.

FIG. 4 is a reduced schematic side view of the excava- "ice tor andcounterweight removal arrangement of FIG. 1 showing the front end of theexcavator in an elevated position,

FIG. 5 is a view similar to FIG. 3 but showing a hydraulic excavatorincorporating another form of counterweight removal arrangementembodying the invention,

FIG. 6 is a fragmentary schematic side view of a hydraulic excavatorincorporating still another form of counterweight removal arrangementembodying the invention,

FIG. 7 is a schematic rear view of the excavator and counterweightremoval arrangement shown in FIG. 6, and

FIG. 8 is a fragmentary side view of the excavator and counterweightremoval arrangement of FIG. 6 showing the excavator in a tiltedposition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, andparticularly to FIGS. l4, there is shown a hydraulic back-hoe type ofexcavator 1 which is more or less conventional in overall constructionand includes a crawler type carrier vehicle designated by the referencenumeral 2. The excavator 1 also includes a working frame 3 which isrotatably mounted on the carrier vehicle 2 and which includes amachinery platform 4 and a machinery housing 5 that encloses theoperating machinery. The excavator 1 also has a boom 6 pivotally footedon the machinery platform 4, parallel hydraulic hoist cylinders 7 (onlyone of which can be seen), a handle 8, a hydraulic dig cylinder 9, abucket 10 and a hydraulic wrist cylinder 11. It will be apparent as thisdescription progresses that other specific forms of machines might beprovided with a counterweight removal arrangement according to thisinvention, so long as they include some boom or equivalent means toraise one end. For this reason, and since the construction and operationof the excavator 1 are well understood by those skilled in the art, thevarious elements thereof are not shown and will not be described ingreater detail.

The excavator 1 is provided with a counterweight 13 received in asuitable recess at the lower rear end of the working frame 3 so as tocounterbalance loads handled by the bucket 10 and thereby increase theload handling capacity of the excavator.

As best seen in FIGS. 1 and 2, the top surface of the machinery housing5 is provided with a pair of aligned, horizontally spaced, U-shapedsupport brackets 14. The support bracket 14 are themselves supported bysuitable struts or other frame elements (not shown) within the machineryhousing 5. The brackets 14 serve as a mounting for the ends of acounterweight support shaft 15 which extends transversely between andthrough suitable openings in the brackets 14 to overhang both sides ofthe machinery housing 5 at the rear thereof. Near each end, the shaft 15is provided with a circumferential groove 16.

Vertically suspended from each end of the shaft 15 is a turnbucklesuspension member 17. Each turnbuckle 17 includes a threaded sleeve 18and an upper rod'19 and a lower rod 20, each such rod having an innerthreaded end received in the sleeve 18 and an outer loop end. The loopsof the upper rods 19 are pivotally supported in the circumferentialgrooves 16 on the shaft 15. With this turnbuckle construction, theoverall length of each member 17 can be varied by rotating the sleeve18. This construction is quite desirable, but other forms of extensibleand retractable suspension members, such as hydraulic cylinders, may beused if desired.

The counterweight 13 has apertured U-shaped brackets 22 suitablyattached to or formed on each side of its top surface under respectiveends of the shaft 15. The loop ends of the lower suspension member rods20 are removably and pivotally attached to respective brackets 22 bytraverse pins 23, the counterweight 13 thus being sup ported by themembers 17. The pins 23 can be held in place by any suitable means suchas, for example, spring clips (not shown) at each end thereof.

As best seen in FIG. 3, the middle portion of the counterweight 13 issubstantially L-shaped in cross section, comprising a horizontal bottomleg 24 Which fits closely against the underside of the rear end of themachinery platform 4 and a vertical rear leg 25 which fits snuglybeneath a rear overhanging portion of the machinery housing 5. To securethe counterweight 13 against movement and to help support it when it isin mounted or working position, the counterweight 13 is connected andlocked to the machinery platform 4 by bolts 26 which extend through boltholes 27 in the counterweight 13 and aligned holes 28 in the platform 4.There is preferably a set of two forwardly and rearwardly spaced bolts26 and holes 27, 28 at each lateral end of the counterweight 13, and onesuch set is seen in FIG. 3. To insure proper orientation of thecounterweight 13 and resulting alignment of the bolt holes 27, 28 whenthe counterweight 13 is moved into mounted position a pair of taperedcentering plugs 29 (only one of which can be seen) are provided on theplatform 4, with one plug 29 being between the members of each pair ofbolts 26. The plugs 29 project downwardly from the underside of theplatform 4, and are received in tapered, mating cavities 30 provided onthe top surface of the leg 24. Although the structure shown is quitesatisfactory, other means of locking and orienting the counterweight 13can be employed.

In FIGS. 1-2, the counterweight 13 is shown in mounted or workingposition wherein it is raised and close to the working frame 3. Thecounterweight suspension members 17 are fully vertical and the pins 23are in place. The counterweight 13 is bolted securely to the machineryplatform 4 and is supported primarily by the bolts 26 and to a lesserextent by the suspension members 17, shaft 15 and brackets 14.

When the counterweight 13 is to be dismounted, the excavator 1 is firstmaneuvered into a position such that the rear end of its working frame 3is directly in front of a supporting block or crib 31 seen in FIG. 4.The bolts 26 are then removed to free the coutnerweight 13 from theplatform 4. The turnbuckle suspension members 17 are then extendedslightly by turning the sleeve 18, this extension serving to lower thecounterweight 13 a short distance sufficient to swing clear of the lowerrear edge of the housing 5 and associated elements such as the plugs 29when the excavator 1 is tilted as will be described.

The next step in dismounting the counterweight 13 is for the operator toelevate the front end of the machine. This is accomplished inconventional fashion by lowering the boom 6 and pressing the bucket 10against the ground until the machine reaches the tilted position of FIG.4. As the front end raises, the rear end pivots about the rear end ofthe carrier vehicle 2, and the counterweight 13 swings downwardly andrearwardly about a pivot point defined by the shaft 15. When the machinereaches the position of FIG. 4, the counterweight 13 has been brought torest on the supporting crib 31. When this has occurred the lower ends ofthe suspension members 17 are disconnected by removing the pins 23, andthe operator can then raise the boom 6 to bring the excavator 1 back toits normal, untilted position.

To effect remounting, the counterweight 13 is first moved to itsdismounted position on the crib 31 in whatever manner is appropriate.Thereafter, essentially the reverse of the foregoing dismountingprocedure is followed, with the excavator 1 being tilted, the pins 23inserted, the excavator lowered, the members 17 retracted and the bolts26 reinserted. It is during retraction of the members 17 that the plugs29 and recesses 30 come into play, insuring that the counterweight 13 isbrought into place with its holes 27 in alignment with the holes 28 ofthe platform 4.

FIG. 5 illustrates a second embodiment of the counterweight removalarrangement of the invention, and like reference numerals have been usedfor like elements. Un like the arrangement hereinbefore described, inthis embodiment there are suspension members 33 which are of a unitary,non-extensible construction. In order to insure that the counterweightwill nevertheless clear the lower rear edge of the platform 4 andhousing 5 when the front end of the excavator 1 is lifted, there is asomewhat modified counterweight 13a in which the upper surface of thebottom counterweight leg 24a slopes or curves down warclly and to theleft as seen in FIG. 5, and the upper surface of the rear counterweightleg 25a slopes or curves downwardly and to the right as seen in FIG. 5.Alternatively, the suspension members 33 can be made long enough so thatthe counterweight 13 is, when in mounted position, spaced a sufficientdistance below the rear of the machinery housing 5 and machineryplatform 4 so that there will be adequate clearance when the excavator 1is tilted. No centering plug is shown, and with a non-extensiblesuspension member the use of an orienting plug and cavity is notfeasible. If desired, however, a plug could be used with a groove in thetop surface of the counterweight that opens through its forward surface.

FIGS. 6-8 illustrate a third embodiment of the counterweight removalarrangement of the invention, and again like numerals have been used forlike parts. In this embodiment, a pair of upwardly extending, elongated,U- shaped counterweight support brackets 34 are mounted at the rear ofthe machinery platform '4, suitable recesses 41 being provided thereforin the housing 5. At the top of the arms of the brackets 34, there arecutout portions or notches 35. The lower rear edges of the brackets 34in this instance are curved to insure that the counterweight will clearsuch edges when the front end of the excavator is elevated. Acounterweight 36 has brackets 37 on the top surface thereof, and aunitary, non-extensible, strut like suspension member 38 is pivotallyattached at the lower end thereof to each bracket 37 by means of aremovable pin 39. The upper ends of the suspension members 38 areprovided with trunnions 40 that project outwardly on opposite sides ofsaid members and which are cradled in the notches 35 to pivotallysupport the counterweight 36. As can be seen in FIG. 7, thecounterweight 36 is provided with a pair of oppositely disposed sideflanges 42 that extend forward, closely alongside the rear side portionsof the platform 4. The flanges 42 and an adjacent side of the platform 4are provided with aligned bolt holes 43 and 44, respectively, throughwhich bolts 45 are passed so that counterweight 36 can be locked inmounted, working position.

When the counterweight 36 is to be dismounted, the locking bolts 45 arefirst removed from the bolt holes 43, 44. As the front end of theexcavator 1 is elevated, the counterweight 36 swings down and away fromthe rear end of the machinery platform 4 and is brought to rest on acrib 31. Continued elevation of the front end of the excavator 1 willcause the rear end thereof to be lowered further and result in thetrunnions 40 at the upper end of each suspension member 38 automaticallymoving out of the bracket notches 35, whereupon the suspension members38 can be folded downwardly as shown in dotted lines in FIG. 8 toeffectively disconnect the counterweight 36. The reverse of theforegoing dismounting procedure is followed for rernounting thecounterweight 36.

While I have illustrated and described my invention herein in preferredforms for use with a back-hoe type of hydraulic excavator, it will bereadily appreciated that the invention is equally useful with othermachines, such as certain front end loader types of hydraulicexcavators, which require a removable counterweight, and which have thecapability of lifting one end. Furthermore, although preferred forms ofthe invention have been shown and described, variations are possiblewithout departure from the spirit of the invention. Instead of using apair of counterweight suspension members, for example, a singlesuspension member centered at the rear of the working frame could beemployed. In view of these and other possible modifications in structureand application, the invention is not intended to be limited by theshowing herein, or in any other manner, except insofar as mayspecifically be required.

I claim:

1. In a hydraulic excavator or the like having a working frame, a boomat the front end of the frame, and boom operating means adapted to applya positive downward pressure on the boom whereby such boom can be workedagainst the ground to elevate the front end of the excavator to producea tilt at the rear, the combination therewith of:

counterweight mounting means positioned at the rear of the excavator ata substantial height above said working frame;

a counterweight having second mounting means thereon; and

an elongate suspension member having an upper end pivotally connected tosaid counterweight mounting means and a lower end connected to thesecond mounting means on the counterweight to thereby mount thecounterweight in pendulum fashion with its center of gravity beneath theelongate suspension member, the counterweight thereby being adapted toswing, in response to gravity, down and away from the rear of theworking frame upon elevation of the front end of the excavator, and atleast one end of said suspension member being releasably connected toits respective mounting means to detach the counterweight from theexcavator.

2. In a hydraulic excavator or the like having a working frame, boommeans at the end of the frame adapted to elevate said front end, and acounterweight mounted closely beneath the rear end of the working frame,the combination therewith of:

first mounting means on the working frame above the counterweight;

second mounting'means on the counterweight; and

a suspension member having an upper end pivotally connected to the firstmounting means and a lower end pivotally connected to the secondmounting means, the counterweight being adapted to swing down and awayfrom the rear end of the frame upon elevation of the front end of theframe, at least one end of said suspension member being releasablyconnected to the respective mounting means, and said suspension memberis extensible and retractable to enable the counterweight to be lowereda sufficient distance below the frame so that the counterweight canswing clear of said frame without interference.

3. The combination of claim 2 wherein there is an orienting plugprojecting outwardly from the lower rear portion of the working frame,and a mating cavity on the counterweight which receives the plug toorient the counterweight.

4. In a hydraulic excavator or the like having a working frame, boommeans at the front end of the frame adapted to elevate said front end,and a counterweight at a lower rear portion of the frame, thecombination therewith of:

first mounting means on the Working frame above the counterweight havinga support bracket with an upwardly opening notch at its top;

second mounting means on the counterweight; and

a suspension member having a transverse trunnion near its upper endadapted to be removably cradled in said notch and a lower end pivotallyconnected to the second mounting means, the counterweight being adaptedto swing down and away from the rear end of the frame upon elevation ofthe front end of the frame.

References Cited UNITED STATES PATENTS 701,887 6/1902 Jackson. 2,722,32011/1955 Dobeus et al 21249 X 3,375,021 3/1968 Grider 212-49 X HUGO O.SCHULZ, Primary Examiner

